Refractory ceramic products, also referred to below as “refractories”, are used for protection against high temperatures in many industrial plants. The most important refractory material types are:                shaped dense products, with a porosity ≦45 vol. %, such as bricks and building components,        shaped thermally insulating products, with a porosity ≧45 vol. %, such as lightweight refractory bricks,        unshaped refractory products, such as refractory concretes, ramming mixes, spraying mixes and the like.        
Conventional refractory products are produced from powder raw materials. The grain size of the powder lies in a relatively broad range, between a few micrometers up to several millimeters. In isolated cases, raw materials with a particle size >10 mm are also used. Correspondingly, the powders are described as coarse-grained, medium-grained, fine-grained and ultra fine-grained particle fraction.
From the state of the art, solid, branched or cross-linked, high molecular weight organo-modified siloxanes or solid phenylmethylpolysiloxanes are known. WO 93/01146 relates to a binder for thermoplastic molding mixes containing at least one thermoplastic silicone resin, with a softening point between 30° C. and 200° C., for the production of molded parts from ceramic or metal from the corresponding ceramic or metal powders. Such thermoplastic molding mixes are used inter alia in processes such as ceramic injection moulding, extrusion or hot pressing, wherein temperature-dependent flow behavior is necessary. Such silicone resins are according to WO 93/01146 preferably used without catalysts, so that further cross-linking and curing during the molding process does not occur.
The use of these aforesaid solid siloxane compounds as ceramic binders has the disadvantage that very homogenous mixtures with ceramic materials are inadequately produced or they are not produced at all. Moreover, with the use of such binders, a sufficiently high green strength of the ceramic product molded from ceramic particles cannot be obtained without a heat treatment at higher temperatures. A further disadvantage of prior art binders is that very high firing temperatures, usually over 1000° C., are needed in order to obtain refractory ceramic products with adequate mechanical properties such as cold crushing strength. Moreover, high pressures and long firing times are needed, which is associated with high energy consumption.
Furthermore, WO 93/01146 relates to a binder for thermoplastic molding mixes, wherein the molding mixes are exclusively processed plastically above the softening point of the silicone resin, and introduced under pressure into molds whose temperature lies below the softening point of the silicone resin. According to the teaching of WO 93/01146, molded, ceramic products with adequate green strength cannot be produced by non-plastic processing, for example uniaxially or isostatically pressed, by slip casting, by ramming, or spraying, in particular at temperatures below the softening point of the silicone resin or the like. In addition, unshaped ceramic products, in particular refractory materials, cannot be produced with the binder and process described in WO 93/01146.
In view of the above, there is a need for a reactive liquid binder that overcomes the drawbacks of prior art binders discussed above, which binder can be used for the binding of ceramic particles for the production of ceramic products.